The present disclosure relates to measuring bias temperature instability induced ring oscillator frequency degradation, and more specifically, to methods that, after enabling an operating state of a ring oscillator, steps up from an initial voltage to a stressing voltage in the ring oscillator, where the initial voltage is approximately one-half the stressing voltage.
Both negative and positive transistor bias temperature instability (BTI) is a major reliability concern for advanced complementary metal oxide semiconductor (CMOS) technologies. Bias temperature instability causes device threshold voltage drift and output current degradation, which degrades circuit performance degradation over time. Bias temperature instability is extremely challenging to measure accurately and conventional methods that characterize the effect of bias temperature instability on circuits have focused on investigating various circuit topologies.